Tensile and fracture toughness of friction stir welded Al-Cu (2024) joints for different artificial ageing conditions
By Dimitrios Karanikolas (University of Aegean), Theno Examilioti (University of Aegean), Nikolaos Alexopoulos (University of Aegean), Li Wenya (Northwestern Polytechnical University, Xi'an,China)

In the present work, the tensile mechanical behavior and fracture resistance of both reference and friction stir welded (FSWed) specimens, of aluminum alloy 2024-T3 with nominal thickness of 3.2 mm, were investigated. Three different ageing times were employed, for heat treating the sheets before the welding procedure (BWHT) at 170oC, corresponding to under- (UA), peak- (PA) and over-ageing (OA) conditions. Tensile specimens according to ASTM E8 specification, with 50 mm gauge length, were machined from the longitudinal (L) direction of the welded sheets, with the joints being located at the middle of the gauge length. FSWed specimens presented approximately the same yield stress, despite the ageing condition of the material, while tensile elongation at fracture was artificial ageing dependent. Fracture toughness was evaluated according to the ASTM E561 standard and was correlated with the resulting ageing microstructure.